Erith has been since 1965 a district of southeast London within the London Borough of Bexley. It is adjacent to the River Thames, where it meets Coldharbour Point in the London Borough of Havering at the opposite end. Erith lies northeast of Bexleyheath and north west of Dartford. It contains much industrial land, although the east is mostly rural land consisting of salt marshes.
The Local Government Act 1894 brought into existence Erith Urban District, which became the Municipal Borough of Erith in 1938. The municipal borough included the communities of Northumberland Heath and Belvedere. The "new town" of Thamesmead was built in the late 1960s and early 1970s.
For more information, see the EN Wikipedia article Erith.